The Contractor will perform a study of the infant care-taking practices of approximately 10,000 mothers at the time of their child's birth, and at 1, 3 and 6 months of age to (1) document changes in infant sleep position in two geographic areas (Boston, Massachusetts and Toledo, Ohio Metropolitan statistical Areas) in a two year period, (2) examine the reasons for and predictors of such changes, (3) examine the correlation, if any, between the prevalence of infant sleep positions and SIDS incidence in each study area, and (4) examine the correlation, if any, between the prevalence of infant sleep positions and non-SIDS health outcomes.